(TLDR: I played a hobbyist horror game that did sound so well that I had to remove my headphones to finish it)
So, I've literally played hundreds of horror games if you include all the free ones on itch and other places, and I almost never get scared, though jumpscares can still wear me out.
Anyway, there was a hobbyist game (because I've played hundreds of them, I can't think of the name and have no idea where I even found the game) that really unnerved me to the point that I had to change the way I was playing it. I'm not sure I've ever done that in a horror game before. It was all psychological. The game starts slow with you arriving at a house in the boonies that you have just purchased. You wander around the house and look at all the creepy/spooky things, which really aren't that bad. The game gives you three chores to do and tells you when you are done to lock the front door, which will advance you to the next night.
So the first day I do the chores and lock the door. The second night starts, and the ambient sounds begin. It's as if the world has sped up a little. I start to do my chores, and the horror picks up a little too. There's an old woman in a rocking chair I can only see if I look from a certain angle. There seems to be blood streaked across the floor in the bedroom, and you can barely hear a woman whimpering. I'm done with my chores and lock the door.
The next night begins and the ambient sounds speed up and get louder. It's beginning to feel more hectic. Everything in the house gets worse. The whimpering is louder, and now I can hear crying coming from somewhere. The night ends in a jumpscare that gets my heart racing. I lock the door.
The next night and the ambient sounds are having an impact on my mental well-being. They are loud and rhythmic and fast. Everything has gone to hell. A jumpscare gets me right away. The bedroom is the last place I want to go. The whimpering and crying are almost unbearable. Somehow I finish the chores and lock the door.
The next night begins and the ambient sounds represent absolute insanity. They are loud, fast and overwhelming. I start to panic before anything else happens. My emotional well-being is being seriously challenged. The woman in the rocking chair stands and disappears while laughing insanely. I can hear the whimpering and the crying, too, and I'm nowhere near the bedroom. My first chore has me going there. I'm not going to do that with this noise. I take my headphones off, calm down, and go to the bedroom where the game ends.
Sound is grossly underutilized in horror games. This game pretty much broke me with it.